1 . Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device in which a semiconductor chip is mounted onto a flexible substrate.
2 . Description of the Related Art
For example, there are known technologies called tape carrier package (TCP) and chip on film (COF) as technologies for mounting a semiconductor device in a liquid crystal display device. Along with development of highly-integrated or highly-functional ICs, JP 06-314724 A and JP 11-102937 A disclose a technology involving forming wiring on a back surface side of a flexible substrate via a via hole to improve flexibility in arrangement of lead wiring in the TCP or the COF.
On the other hand, along with the increase in operating speed for a semiconductor device, an amount of heat radiated from a semiconductor chip is also becoming gradually larger. For that reason, in recent years, even in a semiconductor device including a semiconductor chip arranged on a flexible substrate such as the TCP, a semiconductor device having an excellent heat discharge function has been required.
Conventionally, in the semiconductor device including the semiconductor chip arranged on the flexible substrate, heat radiated from the semiconductor chip is discharged by using a wiring layer connected to the semiconductor chip. However, through the heat discharge only by the wiring connected to the semiconductor chip, sufficient heat discharge performance may not be achieved in the recent semiconductor device.
As described above, through the heat discharge only by the wiring connected to the conventional semiconductor chip, the sufficient heat discharge performance may not be achieved.